Got back from my 600 service - WOW that was expensive! Every since I got the bike - I have had these problems with the idle. When the bike is hot and it's been sitting on a hot day for about 30min or so, when I start it - it idles very randomly between 1240rpm and a dying 900rpm and tons of exhaust fumes. The Yamaha dealer has said that they have found two other bikes with the same problem and are checking on the solution - mine is set to go in and have an O.. something something sensor replaced. I'll keep you updated if anyone else had this problem, but thank the lord it is under warranty!